1996 460ci given to me but has issues

I inherited a 1996 F250 with the stock 460 EFI setup and 170K on the engine. The former owner started to take the engine apart but got about 2 hours in and decided to give the truck to me.

Issue it had when it last ran:

1. 30LBS compression in #6 cylinder
2. Blowing oil out the PCV valve into the air cleaner box

So I pulled off the intake and head to investigate. The anti-freeze pooled inside the cylinders for about a half hour while I was making a place to set the head and to check the valves so forth. None of the antifreeze seeped down nor was there any scarring or marks inside any of the cylinders. The pistons all looked ok as well. So I guess I am stuck with no obvious visual signs and kind of asking for thoughts and theories on what it might be.

Check the Heads out for Cracks and have a valve job done.

The Rings could also be bad in the one cylinder.

If it was mine, I'd pull it down and freshen (Rings, Bearings, Gaskets, Timing Chain and Oil Pump) your 1/2 way their now.

A little background and my intentions. I just want to get this truck in operational condition for the bare minimal required (not going to cut corners, just not a full rebuild right now). The chasis is part of a project I have going and I have another engine and drivetrain to stick in this truck. However I need at least one of them going to make this happen (the donor truck is a working unit right now). Hopefully that explains things a bit.

I traded for a 94 460 last week. Same problem. Took it out of the truck and tore it down to find a burnt exhaust valve.

Valve Job and Gaskets.......and Live with a weak cylinder if its the rings in #6.......

Here are some pics I took earlier. The debris in the cylinder was from stuff falling in when I lifted the head out.






#5 cylinder had the park plug out for a few months before I got the truck and it appears some slight rust made it in there.

Get the heads checked out first. If they are OK and not leaking and the head gasket looked good by that weak cylinder than it sounds like rings are in order...


And unless you cleaned or rubbed the head it looks suspect between holes 6 and 7. You can't see any impressions of the gasket there...

I sat the head down on a fender mat right when I took it out and carried it to where the picture were taken so I don't think the marks were rubbed off. I have pictures of the gasket I can upload later when I get home.

What is a good liquid to check the the valve seals/seats with? I don't want to use something that will eat away or gum up the internals.

Alcohol works good.